"It's bad to use charging go for no reason" he said back in episode 4, and yet now uses it just to go to africa without his parent's permission or even a reason

Technically, he didn't use Charging Go to go to Africa, he just took the Sky Rod out. He doesn't use Charging Go until there's actually Juralians. (And of course there were Juralians, because why wouldn't there be.)

They don't even bother trying to explain why the Juralians are stealing golden crowns and stuff.

For all the shit we give Ken for being a little sociopath, the Juralians are also kinda dicks when you get right down to it, though most of that is on their leader being an irrational megalomaniac.

I'm more baffled as to why there would still be treasure hidden in the Sphinx that far into the future, given that pretty much all of the royal tombs of ancient Egypt were thoroughly looted long before most of them were found by modern archeologists.

Also, even if you're the world's only superhero, it seems kind of weird to be getting showered with favors and invitations to exclusive clubs all the time, regardless of the fact that literally all of them are Juralian traps or military bases about to be blown up by Juralians.

“How do you know I’m Chargeman Ken?” asks Ken Izumi, who transforms in front of people, uses “Ken” in both names, wears a helmet with a transparent faceshield, and has been publically identified by other people as Chargeman Ken in past episodes

The Jeeps of the future must have a poor vehicle safety record if they explode on impact. Also, they either got another Jeep during the time it took to make a monument, or the writers forgot/didn’t care that it exploded (it’s probably one of those)